Achievement of minimal clinically important difference in shoulder function after reverse shoulder arthroplasty: a retrospective cohort study

Abstract

Purpose: Reverse shoulder arthroplasty (RSA) is a surgical procedure to relieve pain and improve shoulder function. This study aimed to investigate the percentage of patients achieving a minimal clinically important difference (MCID) in the American Shoulder and Elbow Surgeons (ASES) score following RSA and to examine factors associated with MCID achievement. Methods: This study included 74 patients (26 males and 48 females; mean age 76.9 ​± ​4.7 years) who underwent RSA between January 2019 and July 2022. Patients were grouped based on the change in ASES total score from pre-operative to 1 year post-operative as follows: not achieved group (<16 point change); and improvement criteria achieved group (≥16 point change). Results: Overall, 81% of patients achieved an ASES score change of ≥16 points. There were no significant differences in demographic characteristics between the two groups. However, the not achieved group had a significantly lower pre-operative pain visual analog scale score and a significantly higher pre-operative ASES total score than the improvement criteria achieved group. Logistic regression analysis identified pre-operative ASES total score as significantly associated with MCID achievement (odds ratio ​= ​0.91, 95% confidence interval 0.87–0.96; p ​= ​0.0007). Conclusions: The rate of patients achieving a ≥16 point improvement in the ASES total score after RSA was 81%. A high pre-operative ASES total score was identified as a factor limiting MCID achievement, suggesting that patients with a high pre-operative function may experience less significant post-operative improvement.

Keywords

• Reverse shoulder arthroplasty
• RSA
• Minimal clinically important difference
• MCID
• American Shoulder and Elbow Surgeons score
• ASES score